Dates, without counting on your fingers.
The date calculator for answering "what day is 90 days from now?" or "how many days between March 15 and September 7?". Handles leap years, clock changes and varying month lengths without you having to think about it.
Pick a mode
How many days between two dates? Broken down into weeks, months and years, plus the total in hours, minutes and seconds.
Result
Fill in the dates to see the result.
What it does
- Add or subtract days, weeks, months, years
- Exact difference between two dates (years, months, days)
- Difference in hours, minutes, or seconds
- Business days (excluding weekends)
- Handles leap years correctly
- Locale-aware formatting (DD/MM/YYYY in es, MM/DD/YYYY in en)
Use cases
- 90-day contract expiration
- Countdown to a specific date
- Gestational age for pregnancies
- Business days for delivery estimates
- Anniversaries and countdowns
FAQ
How does it handle leap years?
Using the browser's native Date object, which correctly counts leap years (every 4 years, except those divisible by 100 but not 400).
What about time zones?
You work with calendar dates here, no time of day. All math runs over whole days, so the result is identical in every time zone and never shifts across DST changes.
Do business days include holidays?
We only exclude Saturdays and Sundays. Holidays vary by country and year, so they're not hardcoded. Subtract them manually if needed.
What about Jan 31 + 1 month?
If the target month is shorter, we clamp to its last day: Jan 31 + 1 month = Feb 28 (29 in leap years). It's the most common convention and the result tells you when it happens.
Does it support pre-1900 dates?
Yes — JS Date supports from −271821-04-20 to +275760-09-13. Plenty for genealogy or history.